Since Research in Motion officially released BlackBerry Messenger 5 users have reported issues with the BBM icon disappearing on various builds of the BlackBerry OS.  To make a long story short, BBM 5 isn’t compatible with certain builds of the BlackBerry operating system.

To address this problem, Research in Motion has released KB article KB22308 ,which, basically, just lets you know that RIM is aware of the issue but that they haven’t found a resolution or have a time frame for when they will.  RIM also updated the BlackBerry Messenger page on BlackBerry App World:

  1. Before downloading, please back up your contact list by displaying the menu within BlackBerry Messenger – Options – Back Up. (Available for BBM 5.0 and 5.0.1 users)
  2. Please ensure that you are using RIM or carrier approved BlackBerry® Device Software to avoid compatibility issues that may result in loss of the BBM icon.  For more information, read article KB23968 (http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB23968)
  3. After installing the new version of BBM, please restart your device.

[Via BerryReview]